Process of making dialkyl-barbituric acids.



UNITED STATES PATENT OFFICE,

WILHELM TRAUBE, OF BERLIN, GERMANY. -PROCESS OF MAKING DlAl KY L BARBlTURlC ACIDS No. 822,165. H

Specification of Letters Patent.

-a.tenteo. May 29, 1906.

1'0 all whom it may concern.-

Be it known that I, WILHELM TRAUBE, chemist, a citizen of German residin at 14 Maassenstrasse, Berlin, in t e Kin om of Prussia and Empire of Germany, ave invented a new Process for Making Dialkyl- Barbituric Acids, of which the following is a specification.

If one molecular weight of diethyl-malonyl chlorid or any other dmlkyl-malonyl chlorid is mixed with two to three molecular weights of an etheric salt of carbamic acid and then heated, hydrochloric acid is given off in large quantity and derivates of diethyl-malonic acid or any other dialkyl-malonic acid with the etheric salts are formed. These compounds are thick oils with acidic character.

They may be separated from a small residue of precipitated ammonium chlorid by dissolving them in eth er or alcohol and then causing the solvent to evaporate after filtration. The oils do not contain any chlorin. According to the results of the analysis the formula C H N O mustbe assigned to the com ound formed from diethyl-malonyl chlori and The compound may be named diethyl-malonyl diethyl-carbamate. It will probably be formed from the components in accordance with the following equation:

X coo1 o +2NH2COOR= Y 0001 X CONHOOR 2HCl+ Y O OONHOOR,

wlliere X, Y, and R represent the alkyl radica s.

The new compound diethyl-malonyl diethyl-carbamate 1s difiicultly soluble in cold water, but easily in ether and alcohol. It is easily dissolved in diluted alkali and regained from this solution by an addition of acids.

If the new compound or its homologues are treated with any condensing agent, such as sodium alcoholate, alcohol is given off. Probably a compound of rin -shaped constitution,-a derivate of .the car amic acid, will be formed in accordance with the following equation:

but this compound could not yet be prepared in a free state, as it VGIE easily loses the carboxetyhl oup C000 So, for instance, if the pro not of the reaction between diethylmalonyl diethyl-carbamate and sodium alcoholate is disso ved in water after any alcohol has been eva orated and then acidified by a mineral aci a gas is evolved which will partly consist of carbon dioxid and a com pound will crystallize. This compound is iethyl-malonyl urea. If another dialkyl malonic acid is used, the correspondent homologous dialkyl-malonyl urea will be formed. Instead of sodium alcoholate an other condensing agent may be used in ma g dialkylmalonyl ureasuch as-alcoholic alkali, alkaline amids, alkaline metals, ammonia, conpiintrated or fuming sulfuric acid, and the e. As is well known, diethyl-malonyl urea and its homologues are of importance because of their therapeutic properties.

' Exam 1e: Twenty parts of diethyl-malonyl c orid are mixed with eighteen to twenty parts of carbamate. The mixture is heated to 110 to 150 centigrade (230 to 300 Fahrenheit) till the copious evolution of hydrochloric acid slackens. The formed dlethyl-malonyl diethyl-carbamate is dissolved in absolute alcohol and se arated from small uantities of solid hy-pro ucts by filtering. Then the alcoholic solution of the derivate of carbamate is added to a solution of 2.3 to 6.9 parts of sodium in absolute alcotigrade (212 to 230 Fahrenheit) and acidified afterward by a diluted acid. Then the alcohol is distilled over suitably under di- I lution of hydrochloric acid slackens, treatminished pressure. acid or diethyl-Inalonyl urea precipitates as a crystalline-compound.

Having thus particularly described and ascertained thenature of my invention and in what manner the same is to be performed, I declare that what I claim is A process for making dialkyl-barbituric three molecu ar Weights alkyl-carbamates ata suitable temperature until the copious evo The diethyl-barbituric I ing the dialk-yl malonyl dialkyl-carbamates formed thereb with condensing a ents, as sodium alcoho ate, and isolating t e products of the reaction.

In testimony whereof I have hereunto set my handin presence of two subscribing Wit- 2o IIGSSBS.

Witnesses HENRY HASPER, WOLDEMAR HAUPT.

WILHELM TRAUBE. I 

